INTERNATIONAL JOURNAL OF ENGINEERING, SCIENCE AND - volume 9 issue 7, July 2020

Pages: 10-28

Date of Publication: 01-Jul-2020

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EFFECT OF THERMAL MODULATION ON THE ONSET OF CONVECTION IN WALTERS B VISCOELASTIC FLUID SATURATED POROUS MEDIUM

Author: PRAKASH H N* VISHWANATHA S **

Category: Engineering, Science and Mathematics

Abstract:

The linear stability of Walters B viscoelastic fluid saturated horizontal porous layer is examined theoretically when the walls of the porous layer are subjected to time-periodic temperature modulation. Three types of boundary temperature modulations namely, symmetric, asymmetric and lower wall temperature modulation is considered. A regular perturbation method based on small amplitude of applied temperature field is used to compute the critical values of Rayleigh number and the corresponding wave number. The shift in critical Rayleigh number is calculated as a function of modulation frequency, viscoelastic parameter and Prandtl number. The effect of all three types of modulations is found to be destabilizing as compared to the unmodulated system. This result is in contrast to the system with other types of fluids. Besides, the influence of physical parameters on the control of convective instability of the system is discussed.

Keywords: Thermal modulation, Porous medium, Walter’s B viscoelastic fluid, Convection